Normalize the rectangles

src/rectangle.js

@@ -43,6 +43,8 @@
  * y increases when going to the bottom
  * degrees increases clockwise with 0 being the horizontal
  *
+ * The constructor normalizes the rectangle to always have 0 <= degrees < 90
+ *
  * @memberof OpenSeadragon
  * @param {Number} [x=0] The vector component 'x'.
  * @param {Number} [y=0] The vector component 'y'.
@@ -77,6 +79,35 @@ $.Rect = function(x, y, width, height, degrees) {
     this.height = typeof(height) === "number" ? height : 0;
 
     this.degrees = typeof(degrees) === "number" ? degrees : 0;
+
+    // Normalizes the rectangle.
+    this.degrees = this.degrees % 360;
+    if (this.degrees < 0) {
+        this.degrees += 360;
+    }
+    var newTopLeft, newWidth;
+    if (this.degrees >= 270) {
+        newTopLeft = this.getTopRight();
+        this.x = newTopLeft.x;
+        this.y = newTopLeft.y;
+        newWidth = this.height;
+        this.height = this.width;
+        this.width = newWidth;
+        this.degrees -= 270;
+    } else if (this.degrees >= 180) {
+        newTopLeft = this.getBottomRight();
+        this.x = newTopLeft.x;
+        this.y = newTopLeft.y;
+        this.degrees -= 180;
+    } else if (this.degrees >= 90) {
+        newTopLeft = this.getBottomLeft();
+        this.x = newTopLeft.x;
+        this.y = newTopLeft.y;
+        newWidth = this.height;
+        this.height = this.width;
+        this.width = newWidth;
+        this.degrees -= 90;
+    }
 };
 
 $.Rect.prototype = /** @lends OpenSeadragon.Rect.prototype */{
@@ -257,10 +288,13 @@ $.Rect.prototype = /** @lends OpenSeadragon.Rect.prototype */{
      * @return {OpenSeadragon.Rect}
      */
     rotate: function(degrees, pivot) {
-        degrees = (degrees + 360) % 360;
+        degrees = degrees % 360;
         if (degrees === 0) {
             return this.clone();
         }
+        if (degrees < 0) {
+            degrees += 360;
+        }
 
         pivot = pivot || this.getCenter();
         var newTopLeft = this.getTopLeft().rotate(degrees, pivot);

test/modules/rectangle.js

@@ -36,6 +36,39 @@
         strictEqual(rect.width, 0, 'rect.width should be 0');
         strictEqual(rect.height, 0, 'rect.height should be 0');
         strictEqual(rect.degrees, 0, 'rect.degrees should be 0');
+
+        rect = new OpenSeadragon.Rect(0, 0, 1, 2, -405);
+        Util.assessNumericValue(Math.sqrt(2) / 2, rect.x, precision,
+            'rect.x should be sqrt(2)/2');
+        Util.assessNumericValue(-Math.sqrt(2) / 2, rect.y, precision,
+            'rect.y should be -sqrt(2)/2');
+        Util.assessNumericValue(2, rect.width, precision,
+            'rect.width should be 2');
+        Util.assessNumericValue(1, rect.height, precision,
+            'rect.height should be 1');
+        strictEqual(45, rect.degrees, 'rect.degrees should be 45');
+
+        rect = new OpenSeadragon.Rect(0, 0, 1, 2, 135);
+        Util.assessNumericValue(-Math.sqrt(2), rect.x, precision,
+            'rect.x should be -sqrt(2)');
+        Util.assessNumericValue(-Math.sqrt(2), rect.y, precision,
+            'rect.y should be -sqrt(2)');
+        Util.assessNumericValue(2, rect.width, precision,
+            'rect.width should be 2');
+        Util.assessNumericValue(1, rect.height, precision,
+            'rect.height should be 1');
+        strictEqual(45, rect.degrees, 'rect.degrees should be 45');
+
+        rect = new OpenSeadragon.Rect(0, 0, 1, 1, 585);
+        Util.assessNumericValue(0, rect.x, precision,
+            'rect.x should be 0');
+        Util.assessNumericValue(-Math.sqrt(2), rect.y, precision,
+            'rect.y should be -sqrt(2)');
+        Util.assessNumericValue(1, rect.width, precision,
+            'rect.width should be 1');
+        Util.assessNumericValue(1, rect.height, precision,
+            'rect.height should be 1');
+        strictEqual(45, rect.degrees, 'rect.degrees should be 45');
     });
 
     test('getTopLeft', function() {
@@ -108,6 +141,20 @@
             "Incorrect bottom right point with 135 rotation.");
     });
 
+    test('times', function() {
+        var rect = new OpenSeadragon.Rect(1, 2, 3, 4, 45);
+        var expected = new OpenSeadragon.Rect(2, 4, 6, 8, 45);
+        var actual = rect.times(2);
+        assertRectangleEquals(expected, actual, "Incorrect x2 rectangles.");
+    });
+
+    test('translate', function() {
+        var rect = new OpenSeadragon.Rect(1, 2, 3, 4, 45);
+        var expected = new OpenSeadragon.Rect(2, 4, 3, 4, 45);
+        var actual = rect.translate(new OpenSeadragon.Point(1, 2));
+        assertRectangleEquals(expected, actual, "Incorrect translation.");
+    });
+
     test('union', function() {
         var rect1 = new OpenSeadragon.Rect(2, 2, 2, 3);
         var rect2 = new OpenSeadragon.Rect(0, 1, 1, 1);
@@ -137,9 +184,9 @@
             2,
             1,
             45);
-        var actual = rect.rotate(45);
+        var actual = rect.rotate(-675);
         assertRectangleEquals(expected, actual,
-                "Incorrect rectangle after rotation of 45deg around center.");
+            "Incorrect rectangle after rotation of -675deg around center.");
 
         expected = new OpenSeadragon.Rect(0, 0, 2, 1, 33);
         actual = rect.rotate(33, rect.getTopLeft());